Steady-state flsash visual evoked potentials (SFVEPs) of 30 Hz were recorded for 46 normal subjects (89 eyes )and 35 patients (51 eyes )with optic neuropathy. The visual acuities of 58.8%affected eyes were less than 0.1. The recorded waveforms were analyzed by discrete Foruier transform (DTF). The amplitudes and phases of fundamental response component and second harmonic were abstracted as characteristic values of the waveform.The total abnormal ratio was 80. 4%. The abnormal types showed the reduced amplitudes,reduced amplitude with phase change, the phases changes, and flat wave. The advantages of SFVEPs in clinical application were discussed. （Chin J Ocul Fundus Dis,1994,10:213-215）
This study aims to explore the differences of event related potential (ERP) between attention deficit hyperactivity disorder (ADHD) and normal children, so that these differences provide scientific basis for the diagnosis of ADHD. Eight children were identified to be ADHD group by the diagnostic criteria of DSM IV (diagnostic and statistical manual of mental disorders IV), and the control group also consisted of 8 normal children. Modified visual continuous performance test (CPT) was used as the experiment paradigm. The experiment included two major conditions, i.e. Go and NoGo. All the 16 subjects participated in the study. A high density EEG acquisition instrument was used to record the EEG signal and processed these EEG data by means of ERP and spectrum analysis. P2 N2 peak peak value and spectral peak around 11 Hz were analyzed between ADHD subjects and those in the control group, and then statistical tests were applied to these two groups. Results showed that: ① Under the condition of Go, ADHD group had a significant lower P2 N2 peak peak value than the values in the control group ( P< 0.05); but under the condition of NoGo there was no significant difference in between. ② Compared with the control group, the ADHD group had significant lower spectral amplitude around 11 Hz under the condition of NoGo ( P< 0.05). However, under the condition of Go the difference was insignificant. In conclusion, there is certain cognitive dysfunction in ADHD children. P2-N2 peak-peak value and spectral peak around 11 Hz could be considered as clinical evaluation indexes of ADHD children′s cognitive function. These two objective indexes provide an early diagnosis and effective treatment of ADHD .
ObjectiveTo investigate the value of pattern reversal visual evoked potential (PRVEP) and sweep pattern visual evoked potential (SPVEP) in evaluating the visual function of patients with central serous chorioretinopathy (CSC).MethodsA retrospective clinical trial. A total of 38 monocular CSC patients were enrolled from March 2016 to December2018 in Heping Hospital Affiliated Changzhi Medical College. There were 34 males and 4 females with the mean age of 40.0±5.2 years. All patients undergo PRVEP detection in both the acute phase (disease course ≤ 3 months) and the clinical cure phase (disease course ≤ 6 months) using the German Roland electrophysiological RETIport system.The stimulation pattern adopted a checkerboard with 1.00° and 0.25° stimulation angles. The P100 peak amplitude and peak time were observed. SPVEP inspection equipment and methods were the same as PRVEP, and the spatial frequency was 1, 2, 4, 6, 8, 12, 16, 22 cpd. The difference between SPVEP vision and subjective vision were compared. The PRVEP peak amplitude, peak time and SPVEP amplitude and phase of the affected eye and the contralateral eye were compared by paired t test; the subjective vision and SPVEP visual acuity of the affected eye and the contralateral eye were compared by Wilcoxon paired rank test; Pearson product-moment correlation analysis was performed on SPVEP vision.ResultsIn the acute phase, the peak amplitude of P100 in the affected eye was lower than that in the contralateral eye (t=30.26, 13.59), and the peak time was prolonged (t=－19.89, －29.41). The difference was statistically significant (P＜0.01); in clinically cured period, the P100 peak amplitude (t=1.49, －0.57) and peak time (t=－1.22, －1.84) of the affected eye and the contralateral eye showed no significant difference (P＞0.05). In the acute phase, the difference in SPVEP amplitude between the affected eye and the contralateral eye with different spatial frequencies was statistically significant (P＜0.01); the phase of the affected eye and the contralateral eye were compared about the spatial frequency 1, 2, 4, 6, 8, 12 cpd, the difference was statistically significant (P＜0.01). During the clinical cure period, the spatial frequency of 6, 8, 12, 16 cpd, the SPVEP amplitude of the affected eye and the contralateral eye, the difference was statistically significant (P＜0.01); on the spatial frequency of 6, 8, 12 cpd, the phase of SPVEP was compared between the affected eye and the contralateral eye, the difference was statistically significant (P＜0.01). During the acute phase and the clinical cure phase, the SPVEP visual acuity of the affected eye was lower than that of the contralateral eye, and the difference was statistically significant (P＜0.01); during the acute phase and clinical cure phase, the SPVEP visual acuity of the affected eye and the contralateral eye were lower than the subjective vision. The difference was statistically significant (acute phase: Z =－5.38, －3.00; P＜0.001, 0.003; clinical cure phase: Z=－5.36, －5.38; P＜0.001,＜0.001). In the acute phase, the subjective visual acuity of the affected eye was positively correlated with SPVEP visual acuity (r=0.847, P＜0.001).ConclusionsPRVEP and SPVEP are useful for objectively assessing the visual function of the patients with CSC. Especially, the slight and potential visual impairment in CSC can been detected by SPVEP.
Injury of dorsal root ganglia (DRG) may cause sensory and motor dysfunction. In order to investigate the changes of somato-sensory evoked potential (SEP) and histological characteristics of DRG in different causes and different periods of injury, fifty-two rabbits were chosed to build the models. The rabbits were divided into 4 groups: Control group (n = 4); mechanical compressing group (n = 16); inflammatory injury group (n = 16); and treatment group (2% lidocaine with hydroprednisone was administered locally, n = 16). After one to eight weeks, SEP was determined and samples of DRG were obtained to observe the histological and ultrastructural changes every week. The result showed that the gap junction of microvascular endothelium in DRG had been destroyed by the mechanical compression was the major cause of the vessel permeability increasing. The increasing of endothelial pinocytic vesicles transportation and widening of endothelial gap junction were the main causes of inflammatory irritation of DRG. The local infiltration with 2% lidocaine and hydroprednisone could obviously ameliorate inflammatory injury in DRG.
Objective To investigate the characteristics of multifocal visual evoked potential (mf-VEP) in healthy individuals, and provide normal reference values for its clinical application. Methods The mf-VEP of 37 healthy individuals (70 eyes) were examined by VERIS ScienceTM4.0. The visual stimulus was adart board with patterns consisted of 60 patches spanning a 25°visual field. The length of m-sequence was 214-1. The results were recorded by bipolar occipital straddle. The signal was amplified 100 K and was put through a band-pass filter between 3 and 100 Hz. The first slice of the second order kernel was analyzed by VERIS software. The summed responses of fields with different stimulus were a nalyzed and compared according to different ages, genders and eyes.Results The latencies and response densities of amplitude had statistically significant differences both in dimidiate and quartered field（Plt;0.05）. The latencies in ≥50 year group were much more delayed in some sectors of the visual field than those in lt; 50 year group（Plt;0.05）. The latencies of women were shorter than those of men（Plt;0.05）. There was no obvious difference of latencies and response densities of amplitude in each field sectors between both eyes（Pgt;0.05）. Conclusions The mf-VEP of healthy individuals can reflect the VEP at different field ocations objectively with its specific physiological characteristics, which may provide normal reference values for its clinical application.(Chin J Ocul Fundus Dis，2003，19：269-332)
Objective To analyze characteristics of solid pseudopapillary neoplasm (SPN) of pancreas and to discuss it’s diagnosis and treatment. Methods The clinicopathologic data of 39 patients with pathologically diagnosed as SPN from January 2012 to July 2017 in the First Affiliated Hospital to Xinjiang Medical University were collected, the clinical characteristics, imaging features, diagnosis and treatment methods, and prognosis were analyzed. Results Among the 39 patients, there were 27 benign SPNs and 12 malignant SPNs. There were no significant differences in the gender, age, blood type, clinical manifestations, distribution of tumor sites, morphological features, and proportions of combined calcification, intracapsular hemorrhage, and pancreatic ductal dilatation between the benign and malignant SPN patients (P>0.050). The maximum diameter of the tumor, the integrity of the capsule, and the ratio of the tumor cystic solidity had significant differences (P<0.050) between the benign and malignant SPN patients. That was, in patients with benign SPN, the largest tumor diameter was less than or equal to 5 cm, and the capsule was complete, and the tumor was mainly cystic and solid. Of the 27 patients with benign SPN, 6 underwent the tumor enucleation, 7 underwent the standard pancreatoduodenectomy, 2 underwent the middle pancreas resection, 5 underwent the standard caudal pancreatectomy, and 7 underwent the spleen-preserving caudal pancreatectomy. Of the 12 patients with malignant SPN, 8 underwent the standard pancreatoduodenectomy and 4 underwent the standard caudal pancreatectomy. All the patients were discharged after surgery and no intra-abdominal infection occurred. The pancreatic leakage occurred in 4 patients and recoved after the full drainage. The average follow-up was 24.5 months, no patient had the tumor metastasis or recurrence, and no patient died. Conclusions Incomplete capsule and the largest diameter >5 cm may suggest malignancy of SPN, and near-solid tumors may be indicative of benignancy. Surgery is a crucial and most effective treatment for SPN, and it is suggested that routine radical operation is performed for malignant SPN.
OBJECTIVE: To prevent the senescence of ’seed cells’ for tissue engineering, the life span of human fibroblasts is extended by reconstitution of telomerase activity, and the osteogenic potential of these fibroblasts are tested. METHODS: The pGRN145 plasmids encoding human telomerase reverse transcriptase (hTERT) were introduced into the normal human primary fibroblasts by electroporation. Telomerase activity was analyzed by TRAP-PCR assay. The beta-galactosidase stain was used to indicate the signs of cell senescence. The hTERT positive fibroblasts were then induced to form bone nodules. The bone nodules were stained by tetracycline and Alizarin Red S. RESULTS: Stable telomerase activity could be detected in the transfected fibroblasts and no signs of cell senescence were found in the fibroblasts cultured for more than 50 doublings. The hTERT positive fibroblasts could form bone nodules when they were cultured in vitro induced by bone morphogentic protein 2 and tumor necrosis factor-alpha. CONCLUSION: The fibroblasts with reconstituted telomerase activity reserve their osteogenic potential.
This paper discusses the relationship between stimulating pulse width and the threshold of electrically evoked compound action potential (ECAP). Firstly, the rheobase and chronaxy from strength-duration curve of nerve fiber was computed using the shepherd's experiment results. Secondly, based on the relationship between ECAP and the action potential of nerve fiber, a mathematical expression to describe the relationship between stimulating pulse width and ECAP threshold was proposed. Thirdly, the parameters were obtained and the feasibility was proved to the expression with the results of experiment using guinea pigs. Research result showed that with ECAP compared to the action potential of nerve fiber, their threshold function relationship with stimulating pulse width was similar, and rheobase from the former was an order smaller in the magnitude than the latter, but the chronaxy was close to each other. These findings may provide meaningful guidance to clinical ECAP measurement and studying speech processing strategies of cochlear implant.
The dysfunction of subthalamic nucleus is the main cause of Parkinson’s disease. Local field potentials in human subthalamic nucleus contain rich physiological information. The present study aimed to quantify the oscillatory and dynamic characteristics of local field potentials of subthalamic nucleus, and their modulation by the medication therapy for Parkinson’s disease. The subthalamic nucleus local field potentials were recorded from patients with Parkinson’s disease at the states of on and off medication. The oscillatory features were characterised with the power spectral analysis. Furthermore, the dynamic features were characterised with time-frequency analysis and the coefficient of variation measure of the time-variant power at each frequency. There was a dominant peak at low beta band with medication off. The medication significantly suppressed the low beta component and increased the theta component. The amplitude fluctuation of neural oscillations was measured by the coefficient of variation. The coefficient of variation in 4-7 Hz and 60-66 Hz was increased by medication. These effects proved that medication had significant modulation to subthalamic nucleus neural oscillatory synchronization and dynamic features. The subthalamic nucleus neural activities tend towards stable state under medication. The findings would provide quantitative biomarkers for studying the mechanisms of Parkinson’s disease and clinical treatments of medication or deep brain stimulation.
A new form of static random-dot stereograms free of monocular clues was designed as stimulus to elicit disparity evoked potentials in 40 normal subjects.A characteristic wide positive wave at about 250ms was consistently recorded in disparity stimulation,which may be regard as evdence of the presence of stereopsis.In constrast,recordings for monocular stimulus all demonstrated a relatively smaller and sharper positive wave with a markedly shortened latency. （Chin J Ocul Fundus Dis,1993,9:214-217）